在andengineandroid中向前跳

我正在开发一个游戏，精灵必须向前跳。 我已经探索过了，使用MoveYModifier向上移动，然后再使用MoveYModifier向下移动。除了在屏幕上点击一次以上，它工作正常。但我想在跳跃时让它向前移动

                 final Entity playerEntity = move;
                 final float jumpDuration = 3;
                final float startX = playerEntity.getX();
                final float jumpHeight = 100;

                final MoveXModifier moveUpModifier = new MoveXModifier(jumpDuration / 2, startX, startX - jumpHeight); // - since we want the sprite to go up.
                final MoveXModifier moveDownModifier = new MoveXModifier(jumpDuration / 2,startX - jumpHeight, startX);
                final SequenceEntityModifier modifier = new SequenceEntityModifier(moveUpModifier, moveDownModifier);

                playerEntity.registerEntityModifier(modifier);
                return true;

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与其使用MoveXModifier，为什么不直接使用MoveModifier呢？

final MoveModifier jumpForward = new MoveModifier(pDuration, pFromX, pToX, pFromY, pToY);